The present invention relates to a CPU cooling arrangement for portable computer and, more particularly, to such a CPU cooling arrangement, which requires less installation space and achieves a high cooling efficiency. The heat sink used in the CPU cooling arrangement provides a broad heat dissipation surface area that dissipates heat quickly from the CPU.
In order to make a portable computer compact for carrying, the thickness must be made as thinner as possible. A regular computer mainframe comprises a motherboard having a CPU socket and a CPU (central processing unit) installed in the CPU socket. The CPU produces much heat during its operation. In order to dissipate heat from the CPU, cooling means must be used. Conventionally, an aluminum-extruded heat sink is used with a fan in a portable computer to dissipate heat from the CPU. In a notebook computer, the keyboard is provided above the motherboard. There is little space between the keyboard and the motherboard for the installation of cooling means. In case a fan is installed, it cannot directly draw outside cooling air into the mainframe from the topside because the keyboard blocks the topside of the computer mainframe. According to conventional designs, aluminum heat plates and/or heat pipes are commonly used in notebook computers for dissipation of heat from the CPU. These conventional designs cannot efficiently rapidly carry heat away from the CPU. Further, regular heat sinks for desktop computers are less efficient for the drawback of limited heat dissipation surface area. Due to limited heat dissipation surface area, a conventional heat sink cannot achieve the desired heat dissipation effect even when a fan attached.
FIG. 1 is an exploded view of a CPU cooling structure according to the prior art. This design of CPU cooling structure comprises a heat sink 2 fastened to the CPU (central processing unit) 11, and a fan 3 fastened to the heat sink 2. The heat sink 2 comprises a contact base 21 disposed in contact with the top sidewall of the CPU 11, a plurality of upright radiation fins 22 upwardly extended from the contact base 21 and arranged in parallel, and a plurality of troughs 23 respectively defined between the radiation fins 22. The fan 3 has a plurality of mounting holes 31 respectively fastened to grooves in the heat sink 2 by tie screws 5. Due to limited heat dissipation surface area of the heat sink 2, this design of CPU cooling structure is not satisfactory in function.
The present invention has been accomplished to provide a CPU cooling arrangement, which eliminates the drawbacks of the conventional CPU cooling designs.
It is therefore the main object of the present invention to provide a CPU cooling arrangement for portable computer, which achieves a satisfactory heat dissipation effect.
According to one embodiment of the present invention, the CPU cooling arrangement comprises a motherboard invertedly fixedly mounted inside the computer mainframe holding the CPU at the bottom side, a heat sink mounted on the CPU at the bottom side, and a fan mounted on the heat sink at the bottom side and facing an air hole in the bottom shell of the computer mainframe for drawing outside cooling air upwardly into the computer mainframe toward the heat sink to carry heat away from the CPU efficiently. According to another aspect of the present invention, the installation of the CPU cooling arrangement enables outside cooling air to be directly drawn into the inside of the mainframe shell of the computer mainframe to carry heat away from the heat sink and the CPU. According to still another aspect of the present invention, the computer mainframe comprises a keyboard disposed at the topside and formed of a metal frame, a circuit board, and a set of key switches, and the motherboard is fixedly fastened with the circuit board of the keyboard to the metal frame of the keyboard.
According to another aspect of the present invention, the computer mainframe comprises a liquid crystal display module disposed at the topside, and the motherboard is fixedly fastened to a bottom sidewall of the liquid crystal display module.
According to still another aspect of the present invention, the computer mainframe comprises a protruded portion disposed in the bottom shell around the air hole and adapted to receive the fan. According to still another aspect of the present invention, the bottom shell of the computer mainframe is a flat shell.
According to still another aspect of the present invention, the heat sink has six sides, the six sides including two opposite open sides selectively for the mounting of the fan and four close sides, a contact base formed integral with one of the close sides, a plurality of radiation fins perpendicularly extended from the contact base and arranged in parallel, the radiation fins each comprising a plurality of protruded portions and recessed portions, and at least one convection trough respectively defined between the protruded portions and recessed portions of the radiation fins.
According to still another aspect of the present invention, the four close sides of the heat sink include a close topside having at least one air vent disposed in communication with the at least one convection trough. Alternatively, the close topside of the heat sink can be made having at least one elongated slot disposed in communication with the at least one convection trough, or having at least one air vent and one elongated slot disposed in communication with the at least one convection trough.
According to still another aspect of the present invention, two fans may be used and respectively mounted in the two opposite open sides of the heat sink.
According to still another alternate form of the present invention, the CPU cooling arrangement comprises a heat sink mounted on the top sidewall of the CPU, the heat sink having a plurality of peripheral sides, the peripheral sides including a plurality of close sides and two opposite open sides, the close sides including one forming a contact base disposed in contact with the CPU, a plurality of radiation fins respectively perpendicularly extended from the contact base, and at least one convection trough defined between the radiation fins; a fan; and a wind box, the wind box comprising an inner wind hole disposed in one end thereof and coupled to one open side of the heat sink, an outer wind hole disposed in an opposite end thereof in communication with a fan hole in the mainframe shell of the computer mainframe, a fan seat disposed in the outer wind hole and adapted to receive the fan, and two mounting flanges respectively disposed at top and bottom sides of the outer wind hole, the mounting flanges each having at least one screw hole respectively fastened to a respective screw hole of the mainframe shell with a respective tie screw. The radiation fins of the heat sink may be directly perpendicularly connected to the CPU. Further, the wind box can be formed integral with a part of the mainframe shell around the fan hole.